Final answer:
Definite resistant HTN is when blood pressure remains high despite three different medications including a diuretic, while Refractory HTN is a severe form of resistant HTN where blood pressure is uncontrolled even with a fourth medication.
Step-by-step explanation:
Definite resistant hypertension (HTN) is a condition where blood pressure remains above the targeted level despite adherence to a combination of at least three antihypertensive medications of different classes, ideally including a diuretic. Patients with this condition must continue to be monitored and treated to prevent complications associated with chronically elevated blood pressure, such as heart attack, stroke, and kidney disease.
Refractory HTN, on the other hand, is a more severe form of resistant hypertension. It is defined as the failure to achieve targeted blood pressure control in patients who are adhering to full doses of an appropriate three-drug regimen (including a diuretic) plus the addition of a fourth medication. This diagnosis suggests a situation where the high blood pressure is non-responsive to treatment, and it often prompts further investigation into secondary causes or assessment of patient's adherence to medication and lifestyle modifications.